Aqueous textile finishing composition containing methylene higher fatty acid diamides



Patented Apr. 27, 1954 AQUEOUS TEXTILE FINISHING COMPOSI- TIONCONTAINING METHYLENE HIGHER FATTY ACID DIAMIDES Frank M. Schofield,Woodstown, N. J., assignor to E; I. du Pont de Nemours and Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationJanuary 9, 1952, Serial No. 265,715

4 Claims. 1

This invention relates to textile finishing compositions andparticularly to compositions which impart water-repellency anddimensional stability to fabrics which are treated therewith.

There has been a demand in the textile trade recently for cellulosicfabrics which are waterrepellent, crease-resistant, dimensionally stableand which have a firm hand. Water-repellency may be obtained by the useof a number of known hydrophobic materials, one of which ismethylenedistearamide. A variety of resins may be applied in order tosecure the desired degree of dimensional stability. The variouswater-repellent agents are insoluble in water and must be applied eitherfrom non-aqueous solutions or from aqueous dispersions. The use ofaqueous media is preferable from the standpoint of economy andconvenience, but is often not possible because of the difficulty inpreparing stable aqueous dispersions of the water-repellent agents.

It is an object of this invention to provide new compositions in theform of stable aqueous dispersions which are inexpensive and easy toapply to textile fabrics, and which produce durable water-repellency anddimensional stability in the fabric. A further object is to provide aprocess by which such stable aqueous dispersions are prepared. Furtherobjects will appear from the detailed description which follows.

The compositions of this invention consist of aqueous dispersions ofmethylene fatty acid diamides, polyvinyl alcohol and preferably awatersoluble lower alkyl ether of a methylol melamine resin. Accordingto the process of this invention, these compositions are prepared by:(1) heating together under vigorous agitation (a) a fatty acid amidemixture which melts between 90 to 100 C. and in which the total contentof stearamide and palmitamide exceeds 80% by weight, (b) water, amolecular excess of formaldehyde, and (d) from 2 to 3% by weight of awater-soluble longchain alcohol sulfate containing from 12 to 18 carbonatoms, based on the weight of fatty acid amides, the said heating stepbeing conducted for at least thirty minutes at a temperature between themelting point of the amide mixture and 100 C.; (2) cooling to atemperature below 80 C., adjusting the pH to below 4. and agitating forat least one hour at 75 to 85 C. (3) filtering off the methylene fattyacid diamides and washing out the excess formaldehyde from the filtercake; (4) mixing the filter cake with from to polyvinyl alcohol inaqueous solution and with from 2 to 5% of a water-soluble long-chainalcohol sulfate containing from 12 to 18 carbon (c1. cam-29.4)

atoms, the percentages in each case being based on the dry weight ofmethylene fatty acid diamides in the filter cake; and (5) mixing theresulting composition with from 0.4 to 7 parts by weight of awater-soluble lower alkyl ether of a methylol melamine resin per part ofmethylene fatty acid diamides.

The fatty acid amide mixture which is employed as a starting material ispreferably the mixture which is sold as technical stearamide. Thisproduct contains small amounts of free stearic acid and ofstearonitrile, up to about 10%, from 50 to stearamide and the balancepalmitamide. Amide mixtures containing large amounts of the amides ofacids having shorter chains do not provide a sufiicient amount ofwater-repellency to be useful in this connection. Such materials may bepresent so long as more than 80% of the amide mixture consists ofstearamide, palmitamide or a mixture thereof. In order to emulsify thefatty acid amide properly with water, it is necessary that the meltingpoint of the amide mixture be less than C. in water. Although purestearamide is reported to melt at 109 C. and pure palmitamide at IDS-107C., the technical grade stearamide melts at about 93-98 C. in water. 7

A molecular excess of formaldehyde must be employed in order to obtainsubstantially complete reaction of the fatty acid amide. This excessmust be at least 10% over the theoretical to replace formaldehyde whichis lost by volatilization. It is ordinarly suitable to use a 25 to 40excess of formaldehyde over the theoretical requirement. A much largerexcess does no harm to the product but produces no correspondingadvantage.

The amount of water present during formation of the dispersion is notcritical so long as enough is added to give a stirrable slurry. Aconvenient amount is from 3 to 5 parts of water per part of fatty acidamide.

Any commercially available water-soluble longchain alcohol sulfate canbe used during the step of dispersing the amide. Particularly useful arethe sodium or triethanolamine salt of the sulfates of the long-chainalcohols obtained by reduction of naturally occurring oils such ascoconut oil and sperm oil. Other surface-active agents such as aromaticand aliphatic sulfonates, the sodium salts of sulfated, unsaturatedlongchain esters such as the monosodium salt of sulfated methyl oleate,a betaine, and a condensate of an alkylphenol with ethylene oxide areeffective in the formation of the initial dispersion.

'3 a The final composition containing the methylene fatty acid diamide,polyvinyl alcohol and resin is, however, substantially inferior whenmade with one of these agents as compared with the composition made witha long chain alcohol sulfate. The preferred amount of the surface-activeagent is from 2 to 3%, based on the weight of the fatty acid amidepresent.

During the initial heating step, some reaction occurs between the fattyacid amides and the formaldehyde, but the reaction does not proceed tocompletion. It is not necessary to control the pli during this period.Depending on the formic acid content of the formaldehyde, the pH at thisstage is ordinarily neutral or'veryslightly acid.

During the second step of the process, in which the mixture is agitatedat a pH below 4 at '75 to 85 9., methylol amides formed in the firststep are converted to the corresponding diamides. Operation in thistemperature range and for at least one hour is necessary in ordertoobtain satisfactory control the-physical form of the product and tosecure complete reaction. Any strong acid may be used to acidify thedispersion to a below 4.

Vigorous agitation of the mixture is essential during the steps offorming the methylene diamide in order that the particle size of theproduct shall be suitably small. The dispersion obtained by this processcontains the methylene diennide in the form of particles which rangefrom about 3.5 to 5 microns.

The dispersion is dewatered by filtration or by any equivalent operationand the filter cake is then washed with water to remove any remainingexcess formaldehyde. The filter cake ordinarily contains about e0 to 50%solids.

The filter calze'is then mixed with polyvinyl alcohol and with asurface-active agent consisting of a water-soluble long-chain alcoholsulfate containing from 12 to 18 carbon atoms. There is added from to30% polyvinyl alcohol, based on the dry weight'of methylene fatty aciddiamides in the filter cake, the preferred amount being from 10 to Thepolyvinyl alcohol can be in the form of a commercial partiallysaponified polyvinyl ester. Polyvinyl aoetate which is from 3G to%%saponified is particularly suitable. lhe'polyvinyl alcohol is added inthe form of an aqueoussolution. v

There is added from '2 to -5%-and preferably from 4 to 5% of thelong-chain'alcohol sulfate, based on the dry weight of methylene'fattyacid diamides. Higher amounts of'the'surface-active agent seriouslyinterfere with the waterrepellent properties of the final product. Asinthe initial dispersion stop, any commercially available water-solublelong-chain alcohol'sulfate, such as the sodium or triethanolamine saltsof thesulfates of the long-chain alcohols-obtainedby reduction ofcoconut oil or'sperm oil, may be used.

The filter cake containing-the methylene diamides is mixed with thepolyvinyl alcohol and the long-chain alcohol sulfate in any efiicientmixer or colloid mill. The resulting mixture is useful directly as atextile finishing composition, producing water repellent effects whenapplied to and heated on the fabrics. The effects are not as durable aswhen resins are also present, nor does the mixture of methylene diamideand polyvinyl alcohol produce any significant degree of dimensionalstability. These mixtures are stable dispersions which may be stored ortransported without adverse effect, and which may subsequently be mixedwiththe'resin described hereaqueous solution,

in to form the preferred compositions of this invention.

The water-soluble lower alkyl ether of a methylol melamine resin, suchas a methylated methylol melamine, is most conveniently incorporatedwith the dispersion of methylene cliamide and polyvinyl alcohol byadding the resin in followed by intimate mixing.

t is sometimes convenient to incorporate the resin immediately prior toapplication of the mixture to the fabric, although stable mixtures maybe prepared in advance and shipped or stored in this state. The amountof resin to be added depends upon the nature of the fabric and of theresin and'on the degree of stiffness and dimensional stability which isdesired. Ordinarily at least 1 part of resin per part of methylenediamide is used, but as little as 9.4 part of resin may be usedsuccessfully. Below this amount of resin, the durability of thewater-repellent efiect is inferior. Amounts of resin up, to about 7partsper part of methyle. e diamide can be used butat this pointthecompositions become undesirably expensive and vlater-repeilencybegins to decrease.

The preparation of the compositions 0f this invention is illustrated bythe following .example:

Example 1 A mintureof 867 parts of-water, ZI'IQPartsof technicalstearamide, 87 parts of'37% formaldehyde and parts of a sodium alcoholsulfate-derived from a mixtureof alcohols containingfrom 1G to 16 carbonatomaprcdominantly lZ-and 14 carbon atoms, is heated to 96 C. withslowagitation to avoid excessive foaming. Thismixturelis then agitated.efficientlyfor one hour at 96 99 C., and cooled to 76 C. 'duringaboutthirty minutes. 'llhenlofi parts of 31% hydrochloric acid are added, andthe temperature rises to vabout 80 C., where it is held for one hourwith fast, efficient agitation. The mixt re gives a deep;blue color withCongo red during this period.

After addition of 209 of water, thecharge is filtered and the cakeiswashed.acid free with water.

parts, containing 40% solids. methylene diamide has .a meltin 13543? C.

The methylene diamide press.v cake .is 1charged into a 40 50 C. solutioncontaining'iili-o:partaof 10% polyvinyl alcohol solution in water'(869.89 saponified polyvinyl acetate) 50 parts --of the same commerciallong-chain alcohol sodium sulfate of about 20% active ingredient used inthe first step, and 10 additionalparts of water. T-he charge is madejust alkaline .to brilliant yellow paper (pl-1:7-8) by the additionof30% jsodium hydroxide solution and .is. agitated at 3040" C.

.until it becomes a smooth,; apparently homogeneous paste. It is thenpassed through an efficient mechanicalmixer to complete themixing.

Theresulting dispersion, amounting to about loooparts, with avn1ethylene dlamide. contentcf abcutfloo parts, is mixed with ,lflOOrparts of commercial methylated methylol melamine.

.When the resulting dispersion is diluted, .mixed .with ammonium acidphosphate and paddedcnto viscose rayon and .thefabrio isdried. and=.,heted for threeminutes at .3'Z5-3-75;C.,;the result ng fabric possessesaihigh degree oi attater-repellency coupled with satisfactory..dimensional ,stability and a firm hand.

Similar results are, .olotained when aonly .2200

parts of methylated methylol melamine are used instead of 1400 parts.

The compositions of this invention are prepared for application to thefabric simply by mixing them into water with a small amount of anyconventional mildly or potentially acidic catalyst for curing the resin.Examples of suitable catalysts include tartaric acid, the ammonium acidphosphates, zinc nitrate and the like. The aqueous dispersion is thenapplied to the fabric by padding or by any other convenient method. Thefabric is dried and baked to cure the resin. A suitable baking period isabout 3 minutes at 325 to 375 F. Generally an application of thecomposition sufficient to give about 1.5 to 3% of the methylene diamideon the fabric is required to obtain optimum results. The treated fabricdisplays excellent water-repellency, crease-resistance and dimensionalstability. The hand of the fabric is improved by becoming firmer andmore resilient. These effects are quite durable and survive washing anddry-cleaning of the fabric. The resin content of the composition servesnot only to contribute crease-resistance and dimensional stability butalso to bind the methylene diamide to the fabric so as to give a moredurable waterrepellent effect.

An important advantage of these compositions is that they are quitestable without close control of the pH. This is not true of many otherwaterrepellent compositions, as for example dispersions in soapsolution, which are extremely sensitive to changes in pH.

I claim:

1. A proces of preparing a textile finishing composition whichcomprises: (1) heating ,together under vigorous agitation (a) a fattyacid amide mixture which melts between 90 and 100 C. in water and inwhich the total content of stearamide and palmitamide exceeds 80% byweight, (12) water, a molecular excess of formaldehyde, and (d) from 2to 3% by weight of a water-soluble long-chain alcohol sulfate containingfrom 12 to 18 carbon atoms, based on the weight of fatty acid amides,the said heating step being conducted for at least thirty minutes at atemperature between the melting point of the amide mixture and 100 C.;(2) cooling to a temperature below 80 C., adjusting the pH to below 4and agitating for at least one hour at 75 6 to C.; (3) filtering off themethylene fatty acid diamides and washing out the excess formaldehydefrom the filter cake; and (4) mixing'the filter cake with from 10 to 30%polyvinyl alcohol in aqueous solution and'with from 2 to 5% of awater-soluble long-chain alcohol sulfate containing from 12 to 18 carbonatoms, the percentages in each case being based on the dry weight ofmethylene fatty acid diamides in the filter cake.

2. A textile finishing composition prepared by the process of claim 1.

3. A process of preparing a textile finishing composition whichcomprises: (1) heating together under vigorous agitation (a) a fattyacid amide mixture which melts between and C. in water and in which thetotal content of stearamide and palmitamide exceeds 80% by Weight, (17)water, (0) a molecular excess of formaldehyde, and (d) from 2 to 3% byweight of a water-soluble long-chain alcohol sulfate containing from 12to l8carbon atoms, based on the weight of fatty acid amides, the saidheating step being conducted for at least thirty minutes at atemperature between the melting point of the amide mixture and 100 C.(2) cooling to a temperature below 80 C., adjusting the pH to below 4and agitating for at least one hour at 75 to 85 C.; (3) filtering offthe methylene fatty acid diamides and washing out the excessformaldehyde from the filter cake; (4) mixing the filter cake with from10 to 30% polyvinyl alcohol in aqueous solution and with from 2 to 5% ofa water-soluble long-chain alcohol sulfate containing from 12 to 18carbon atoms, the percentages in each case being based on the dry weightof methylene fatty acid diamides in the filter cake; and (5) mixing theresulting composition with from 0.4 to 7 parts by Weight of awater-soluble lower alkyl ether of a methylol melamine resin per part ofmethylene fatty acid diamides.

4. A textile finishing composition prepared by the process of claim 3.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,365,813 Gluesenkamp Dec. 26, 1944 2,423,428 Pollard July 1,1947 2,537,667 Harris Jan. 9, 1951

1. A PROCESS OF PREPARING A TEXTILE FINISHING COMPOSITION WHICHCOMPRISES: (1) HEATING TOGETHER UNDER VIGOROUS AGITATION (A) A FATTYACID AMIDE MIXTURE WHICH MELTS BETWEEN 90 AND 100* C. IN WATER AND INWHICH THE TOTAL CONTENT OF STEARAMIDE AND PALMITAMIDE EXCEEDS 80% BYWEIGHT, (B) WATER, (C) A MOLECULAR EXCESS OF FORMALDEHYDE, AND (D) FROM2 TO 3% BY WEIGHT OF A WATER-SOLUBLE LONG-CHAIN ALCOHOL SULFATECONTAINING FROM 12 TO 18 CARBON ATOMS, BASED ON THE WEIGHT OF FATTY ACIDAMIDES, THE SAID HEATING STEP BEING CONDUCTED FOR AT LEAST THIRTYMINUTES AT A TEMPERATURE BETWEEN THE MELTING POINT OF THE AMIDE MIXTUREAND 100* C.; (2) COOLING TO A TEMPERATURE BELOW 80* C., ADJUSTING THE PHTO BELOW 4 AND AGITATING FOR AT LEAST ONE HOUR AT 75 TO 85* C.; (3)FILTERING OFF THE METHYLENE FATTY ACID DIAMIDES AND WASHING OUT THEEXCESS FORMALDEHYDE FROM THE FILTER CAKE; AND (4) MIXING THE FILTER CAKEWITH FROM 10 TO 30% POLYVINYL ALCOHOL IN AQUEOUS SOLUTION AND WITH FROM2 TO 5% OF A WATER-SOLUBLE LONG-CHAIN ALCOHOL SULFATE CONTAINING FROM 12TO 18 CARBON ATOMS; THE PERCENTAGES IN EACH CASE BEING BASED ON THE DRYWEIGHT OF METHYLENE FATTY ACID DIAMIDES IN THE FILTER CAKE.